Crestal unconformities on an exposed Jurassic tilted fault block, Wollaston Forland, East Greenland as an analogue for buried hydrocarbon traps

Structural Inheritance and Rapid Rift‐Length Establishment in a Multiphase Rift: The East Greenland Rift System and its Caledonian Orogenic Ancestry

“…This can be seen already in Vischer's () cross sections from the area between 74°N and 75°N, where dramatic thickness variations were observed across several of the faults, suggesting episodic fault activity in Late Paleozoic to Mesozoic times. During this time, key events recognized in the East Greenland rift system include (i) initial rifting in latest Devonian to Mississippian times (Stemmerik et al, ; Surlyk, ); (ii) rotational block faulting in Pennsylvanian to Early Permian times (Haller, ; Larsen, ; Surlyk, ; Surlyk et al, ); (iii) a Late Permian to earliest Triassic phase of relative tectonic quiescence and thermally driven subsidence (Larsen, ; Surlyk et al, ); (iv) renewed rifting and fault‐controlled subsidence in the latest Early Triassic (Clemmensen, ; Seidler et al, ; Surlyk, ); (v) relative tectonic quiescence in Middle Triassic to Early Jurassic times (Surlyk, ); and (vi) a particularly well‐documented phase of rifting in Middle Jurassic to earliest Cretaceous times (Henstra et al, ; Maync, ; Surlyk, ; Surlyk & Korstgård, ; Vischer, ; Whitham et al, ). This protracted period of rifting culminated in the breakup of the North Atlantic in Paleocene‐Eocene times (Larsen & Watt, ; e.g., Mjelde et al, ).…”

“…It is separated from segment 1 by step A (Figure ), which is a NE‐trending fault that runs ~65 km across Traill Ø and Geographical Society Ø (e.g., Henriksen, ; Surlyk, ), and which had formed and was active by Devonian‐Carboniferous times (Stemmerik et al, ). Segment 3 is the ~170 km long, NNW‐ESE trending Clavering‐Dombjerg Thomsen Land Fault system (Figure ), which saw significant activity during the well‐documented Late Jurassic to Early Cretaceous rift phase (Henstra et al, ; Kristensen et al, ; Surlyk & Korstgård, ); earlier activity (Carboniferous‐Permian?) has also been suggested for this fault system (op.…”

“…This study is focused around samples from outcrops of the Dombjerg Fault, which forms part of the CDTF system (Kristensen et al, ; Surlyk & Korstgård, ), termed segment 3 in the rift fault framework outlined above (Figures , and ). The CDTF system comprises alternating NW/NNW‐trending and NNE‐trending segments, and the Dombjerg Fault is today connected with the Thomsen Land Fault by a NE‐striking “transfer” fault, forming a pronounced dogleg in the map‐view geometry of the fault system (Figures and ; Surlyk & Korstgård, ).…”

“…The main rift phase in Middle Jurassic to Early Cretaceous times is well‐documented by the presence of fault‐ward expanding syn‐rift deep‐water clastics in the Wollaston Forland hangingwall basin (Henstra et al, ; Surlyk, , , ), whereas proposed earlier (Carboniferous‐Permian?) phases of activity (Kristensen et al, ; Surlyk & Korstgård, ) have not been proven. By subjecting five fault gouge samples from the Dombjerg Fault Zone to K‐Ar illite dating, in combination with rigorous review of previously published geochronological evidence, we can, for the first time, place specific age constraints on the timing and episodicity of rifting that caused slip to accumulate in the East Greenland rift system.…”

“…The Dombjerg Fault forms part of the Clavering‐Dombjerg‐Thomsen Land Fault (CDTF) Zone, a regionally significant rift‐bounding fault in the East Greenland rift system. Like many basin‐bounding faults in rift basins, the Dombjerg Fault Zone has likely been active during at least two phases of extensional movement (e.g., Surlyk & Korstgård, ). The main rift phase in Middle Jurassic to Early Cretaceous times is well‐documented by the presence of fault‐ward expanding syn‐rift deep‐water clastics in the Wollaston Forland hangingwall basin (Henstra et al, ; Surlyk, , , ), whereas proposed earlier (Carboniferous‐Permian?)…”